1. Field of the Invention
The present invention relates to an intake controller for an internal combustion engine. In particular the present invention relates to an intake controller provided with an intake vortex generating device which throttles a cross sectional area of an intake passage communicating with a combustion chamber of the engine to generate an intake vortex in the combustion chamber of the engine.
2. Description of Related Art
There is conventionally known a throttle controller for an internal combustion engine which controls a flow quantity of intake air aspired into an internal combustion engine for an automobile or the like, as an intake controller for the internal combustion engine. The throttle controller is, as shown in FIGS. 7 to 9, provided with a throttle body 101 united with an intake pipe for the internal combustion engine and a throttle valve 104 for opening/closing a throttle bore 103 as an intake passage of a throttle bore wall 102 as a casing of the throttle body 101. Further, the throttle body 101 is provided with an actuator such as an electronic motor 106 for driving a shaft 105 as a rotational shaft of the throttle valve 104. The actuator includes the electric motor 106, a gear reduction mechanism (including a pinion gear 111, an intermediate reduction gear 112 and a final reduction gear 113), a sensor cover 107 and the like.
A throttle position sensor is mounted in the actuator for detecting a throttle position corresponding to a valve position of the throttle valve 104. The throttle position sensor is formed of a magnet 121 retained and fixed in the final reduction gear 113, a magnetic detection element of a non-contact type (not shown) retained and fixed in a sensor mounting portion 122 of the sensor cover 107 as facing the magnet 121, and the like. Here, a metallic gear fixing plate 114 is insert-molded in an inner peripheral portion of the plastic final reduction gear 113. In the throttle controller, in general for preventing a relative rotation between the shaft 105, the final reduction gear 113 and the gear fixing plate 114, a fitting portion 123 provided at an end in a rotational shaft direction of the shaft 105 is formed in an elliptic shape as having a width across flat portion 124 and a fitting bore 125 formed inside the gear fixing plate 114 is formed in an elliptic shape as having a width across flat portion 126. Therefore, an elliptic portion 127 of the gear fixing plate 114 is fitted on an outer periphery of the fitting portion 123 of the shaft 105 in such a manner as not to move in the circumferential direction of the shaft 105. On an outer peripheral portion of the final reduction gear 113, a fully closed stopper portion 130 contacting a fully closed stopper 129 when the throttle valve 104 is fully closed and a circular gear portion (formed of many teeth) 131 meshing with the intermediate reduction gear 112 are integrally formed.
As the intake controller for the internal combustion engine, there is, as shown in FIG. 10, known an intake passage opening/closing device for an internal combustion engine which is provided with a housing 141 united with an intake pipe, an intake flow control valve 142 opening/closing an intake passage of the internal combustion engine, a shaft 143 supporting and fixing the intake flow control valve 142 and an actuator driving the intake flow control valve 142 through the shaft 143 (for example, refer to JP2004-028809A and JP2007-68378A). The actuator is formed of an electric motor 144, a worm gear 145, a helical gear 146, a flexible member 147, an output spur gear 151, an input spur gear 152 and the like. Further, a valve position sensor of a non-contact type is mounted in the actuator for detecting a valve position of the intake flow control valve 142. The valve position sensor is formed of a magnet 153 retained and fixed in the input spur gear 152 and a pair of yokes (magnetic body) arranged as opposed to the magnet 153 and magnetized by a magnetic force of the magnet 153, a hole IC 154 arranged in a magnet detection gap formed between the opposing yokes and the like. A fully opened stopper 155 is provided to be capable of contacting the input spur gear 152.
Further, as shown in FIG. 11, there is known an intake controller for an internal combustion engine using a shaft 162 having a vertical cross section in the rotational shaft direction formed in a polygonal shape, as a rotational shaft (drive shaft) for transmitting a driving force of the electric motor 161 to an intake flow control valve (for example, refer to JP2004-124933A). This intake controller is provided with a final reduction gear 164 having a cylindrical portion for rotatably supporting an end in an axial direction of the shaft 162 by a bearing portion 163 in the side of the intake manifold. An insert bore 166 in a blind bore-shape is formed inside a cylindrical portion 165 of the final reduction gear 164. An end of the shaft 162 is inserted in the insert bore 166 which is formed with substantially the same cross section as that of the shaft 162. In consequence, inserting the shaft 162 into the insert bore 166 causes a relative rotation between the shaft 162 and the final reduction gear 164 to be restricted
However, in the throttle controller for the internal combustion engine shown in FIGS. 7 to 9 and in the intake passage opening/closing device for the internal combustion engine described in JP2004-028809A and JP2007-68378A, the final reduction gear 113 or the input spur gear 152 and the magnet 121 or 153 are arranged in the gear fixing plate 114 or the input spur gear body fixed to the shaft 105 or 143. Therefore, even if a rotational slip occurs between the final reduction gear 113 or the input spur gear 152 arranged in the gear fixing plate 114 or the input spur gear body and the shaft 105 or 143, a relative position between the final reduction gear 113 or the input spur gear 152 and the magnet 121 or 153 does not change. In consequence, the magnetic detection element or the hole IC 154 can not detect an abnormal state such as a rotational slip between the final reduction gear 113 or the input spur gear 152 and the shaft 105 or the shaft 143. In addition, in the intake controller for the internal combustion engine described in JP2004-124933A, since the final reduction gear 164 having the insert bore in a blind bore shape is mounted in a tip portion in the rotational shaft direction of the shaft 162, a sensor component (for example, magnet) required to be fixed separately from the final reduction gear 164 can not be mounted to the shaft 162.